Transactions of many types require a system for identifying a person (Who is it?) or for verifying a person's claimed identity (Is she who she says she is?). The term recognition refers to identification and verification collectively. Traditionally, three methods have been used for recognizing a person: passwords, tokens, and biometrics.
Biometrics refers to information measured from a person's body or behavior. Examples of biometrics include fingerprints, hand shapes, palm prints, footprints, retinal scans, iris scans, face images, ear shapes, voiceprints, gait measurements, keystroke patterns, and signature dynamics. The advantages of pure biometric recognition are that there are no passwords to forget or to give out, and no cards (tokens) to lose or lend.
In biometric verification, a user presents a biometric which is compared to a stored biometric corresponding to the identity claimed by the user. If the presented and stored biometrics are sufficiently similar, then the user's identity is verified. Otherwise, the user's identity is not verified.
In biometric identification, the user presents a biometric which is compared with a database of stored biometrics typically corresponding to multiple persons. The closest match or matches are reported. Biometric identification is used for convenience, e.g., so that users would not have to take time consuming actions or carry tokens to identify themselves, and also for involuntary identification, e.g., when criminal investigators identify suspects by matching fingerprints.
A problem faced by biometric recognition systems is the use of counterfeit biometrics to defeat the protections afforded by such systems. The use of counterfeits by unauthorized persons in order to fool the system into providing them access to which they would not otherwise be entitled is also called spoofing. One example is the presentation of a photograph, such as of a fingerprint, hand, or face, to spoof the biometric system. Another example is the presentation of a three-dimensional (3D) fake, such as a rubber hand or a gel finger. Another example is the presentation of a body part taken from a registered user of the biometric system.
Accordingly, it is desirable to provide a method for reducing the possibility that a biometric recognition system will be fooled by a counterfeit biometric. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.